This invention relates generally to improvements in portable warning markers of the type used to divert motor vehicle traffic through and/or around construction sites, areas where painting and/or clean up work is in progress and the like.
Portable warning markers, particularly those of the plastic cone shaped type, have long been known and used in the prior art. Because of their shape, such cone shaped markers, take up a great deal of space during transport and storage, even when stacked one upon the other in groups of six or eight markers per stack. For this reason, there have been a number of attempts made to render cone shaped markers collapsible and foldable as a space saving measure in the storage and transport thereof. See, for example, U.S. Pat. No. 4,466,376 issued to H. D. Wells on Aug. 21, 1984; U.S. Pat. No. 4,256,050 issued to B. G. Barnard on Mar. 17, 1981; U.S. Pat. No. 2,954,005 issued to L. A. Cioffi, et al. on Sep. 27, 1960; and U.S. No. 2,762,327 issued to M. O. Weig on Sep. 11, 1956.
The Wells patent discloses a fan shaped panel of cardboard stock having four triangular faces joined together along adjacent sides by fold lines. The fan shaped panel is formed into a four sided polygon or pyramid, the base of which is attached to a base panel which has portions foldable to form a rectangular wall around the base of the pyramid. While the reference structure is, indeed, foldable, it is foldable only to assemble the structure, not to disassemble it for transport and storage purposes. The cardboard stock from which the marker is made is not very resistant to wet weather, and the base and pyramid components must be disassembled in order to unfold the unit for storage, thus resulting in two distinct broad, flat panels.
The Baker patent discloses a collapsible cone formed from a continuously extended plastic strip wound in a roll upon a base plate. A central handle permits lifting of the inner most turn of the roll which, in turn, lifts successive turns until the strip forms a vertically extending cone shaped helix. Spaced apart projections along the strip prevent the innermost turn from being pulled up so far from the base that successive turns of the helix separate from one another.
An earlier version of a collapsible traffic cone is shown in the Cioffi et al. patent wherein separate cone shaped rings of varying diameter which fit within one another can be pulled up from a relatively flat package to form a cone shaped marker.
The patent to Weig discloses an inflatable cone shaped marker that can be deflated to form a flat package for storage and transport purposes. But this device is dependent upon the integrity of its air valve which is used to inflate and deflate the device, which could be susceptible to slow air leakage over the many months of time that such devices are often used on a highway construction job site. Also, puncture of the casing of this device, as by means of flying gravel, glass or other projectiles caused by passing traffic is a constant threat to its integrity.
Moreover, none of these collapsible, foldable or inflatable markers is adapted for pick-up from a job site for placement on a truck by means of a suitable long handled tool operated by a worker from the truck bed. These prior art devices require that a worker walk along beside a truck, pick up each marker by hand, and either place it onto the truck bed himself, or hand it to another worker stationed on the truck bed. It would be advantageous if such devices were adapted for pick up by a worker stationed on the truck bed using a suitable long handled tool having a single hooked or forked end.
Another difficulty encountered with prior art portable traffic markers is the fact that their bright colored reflective surfaces tend to become dulled by oil, grease, tar and other impurities which build up thereon over a period of time when exposed to motor vehicle traffic and construction around highway job sites where such markers are routinely employed. Many state highway departments, such as in my state of Kentucky, for example, require such dulled markers to be retired from service when their bright surfaces reach a certain level of dullness and/or lack of reflectivity. It has been my experience that the conventional plastic cone shaped markers used around highway construction projects often have a useful in-service life of no more than about six months, and sometimes even less. These markers are relatively expensive to replace so often, especially when used in great volumes over long stretches of interstate highway, often extending for many miles as, for example, between successive access ramps which are often spaced many miles apart in rural areas.
By means of my invention, these and other difficulties encountered when using portable warning markers of the prior art are substantially overcome.